1. Enable the "Create Pages for Categories" setting, in Admin Panel » Options » Node & Forum List 2. Go to Forum list, and make note of any category URL. 3. Disable the "Create Pages for Categories" setting. 4. Visit the URL you noted down in #2. Code: Fatal error: Cannot use object of type XenForo_Link as array in /library/XenForo/Controller.php on line 513 Example: http://xenforo.com/community/categories/official-forums.1/ EDIT: Traced it down to XenForo_Route_Prefix_Categories::buildLink() which returns a XenForo_Link object if "categoryOwnPage" option is false. It should return a plain string.